I'm not good with power, how do I know 20 or 30 is enough for me
First, figure out the average power usage of your servers in amps. This is not the same as the wattage of power supply, and the server maker should be able to tell you. Then decide how many servers you want to be able to put in the rack. Finally, keep your average usage below 80% of the circuit's rating (for a 20A circuit, that'll be 16A) to account for usage spikes during boot.
There's a bit of a range depending on what kind of hardware you're using. If you're using lower end servers, you may be able to put 15 of them on a 20A circuit. If you're using higher end servers, you might only be able to use 5.
Before you go out and buy APC equipment, you need to know what size circuit you'll be using beforehand. 15A, 20A, and 30A circuits all use different plugs. Also be sure to pay attention to voltage, as depending on where your DC is located, the standard might be 120V, 208V, or 240V.
Last edited by bqinternet; 09-15-2006 at 08:31 PM.
I would recommend avoiding products that essentially yank the power cord out of the machine while it is running. Doing this generates a momentary power surge that can damage the computer's power supply, hard drives, and motherboard.
There's a bit of irony to a company like APC that generates several billion dollars in revenue of power conditioning and power protection equipment, and also offers a small line of products that generate some of the same conditions by yanking out the power cord that their power protection equipment was supposed to protect your server from!
There are plenty of hardware-safe alternatives... Since you're using PowerEdge servers, I would recommend Dell's Remote Access Card (DRAC) that provides out-of-band control of your server for reboots when it crashes.
Cory von Wallenstein, Dynamic Network Services Inc.
My team and I spent the last few months putting together the DynDNS Spring Server VPS platform for folks needing IPv4 and IPv6 Linux servers on Xen. Would love feedback, both good and bad!